The court issued the order in favour of Glenmark on Thursday. Shortly after the order to revoke Glaxo’s patent, Glenmark’s generic unit launched a copy of the drug—atovaquone proguanil—in its generic form in the UK.

“Judgement has today been handed down in the case, which involved the revocation of Glaxo’s patent for its anti-malarial product Malarone. Following proceedings in the high court, Justice Arnold revoked Glaxo’s patent on basis that it was obvious,” said the Glenmark note.

Based on pharma market researcher IMS Health’s sales data for the 12-month period ending September 2012, the drug garnered sales equivalent to €20.69 million in the UK.

Glenmark is the first firm to launch the generic version of the drug in the UK. Along with Glenmark, US generic firm Mylan Inc. had also challenged Glaxo’s patent on the drug. But Mylan is yet to launch its generic version, according to a person familiar with the development.

Mint could not immediately reach Mylan on the issue.

“I can confirm the UK patent court has ruled in patent litigation regarding GSK’s product Malarone...,” said David Mawdsley, vice-president (global media) of GlaxoSmithKline Plc, in an email reply to Mint. “We are studying the judgment.”

The court decision relates solely to the UK combination patent for Malarone and does not affect any other jurisdiction. The patent is due to expire in November of this year in other markets, added David.

Glenmark launched the same generic drug in the US in 2011. It hasn’t faced any generic competition in the $70 million market.

Glenmark had filed the petition challenging the patent of Glaxo in the UK high court in September. Glenmark shares closed at Rs.496.55, down 1.52% on Thursday on BSE. The announcement on UK court’s order came after the market hours.